我想使用公用集合4-4.0 ComparatorChain进行排序。

Question

当我们使用最新的公共集合4-4.0jar时，我们会收到一条错误消息，如下所示:使用ComparatorChain和BeanComparator选择排序。你知道这是怎么回事吗？我们对beanutils使用commons utile-1.9.2.jar。

成功代码(共用-集合-3.2.1.jar)

@SuppressWarnings("unchecked")
private void testCommonsChain() {

   ComparatorChain comparator = new ComparatorChain();

   List<TestDataBean> testDataBeanList = this.createTestDataBeanList();

   comparator.addComparator(new BeanComparator<TestDataBean>("name"), true);
   comparator.addComparator(new BeanComparator<TestDataBean>("kngk"));
   Collections.sort(testDataBeanList, comparator);

   this.printData(testDataBeanList);

}

失败代码(公用-集合4-4.0.jar)

private void testCommonsChain() {

    ComparatorChain<TestDataBean> comparator = new ComparatorChain<TestDataBean>();

    List<TestDataBean> testDataBeanList = this.createTestDataBeanList();

    comparator.addComparator(new BeanComparator<TestDataBean>("name"), true);
    comparator.addComparator(new BeanComparator<TestDataBean>("kngk"));
    Collections.sort(testDataBeanList, comparator);

    this.printData(testDataBeanList);

}

错误日志

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/collections/comparators/ComparableComparator
    at org.apache.commons.beanutils.BeanComparator.<init>(BeanComparator.java:87)
    at logic.TestComparator.testCommonsChain(TestComparator.java:36)
    at logic.TestComparator.executeComparator(TestComparator.java:19)
    at myTestOrange.TestMain.main(TestMain.java:10)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.collections.comparators.ComparableComparator
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    ... 4 more

Answer 1

至于它的问题是什么:查看POM文件，commons 1.9.2依赖于collections 3.2.1。问题是，公共-beanutils引用的类不再在collections 4.4.0中可用。